CoplayDev/unity-mcp · error · FileNotFoundError

Package file not found: {PACKAGE_JSON}

Error message

Package file not found: {PACKAGE_JSON}

What it means

Raised as FileNotFoundError by load_package_version() when MCPForUnity/package.json does not exist on disk. This file is the source of truth for the Unity package version and is the first thing update_versions.py reads (when --version is not supplied). REPO_ROOT is derived from the script's own location (parents[1]), so a wrong CWD or relocated script produces a bad path.

Source

Thrown at tools/update_versions.py:48

import argparse
import json
import re
import sys
from pathlib import Path

REPO_ROOT = Path(__file__).resolve().parents[1]
PACKAGE_JSON = REPO_ROOT / "MCPForUnity" / "package.json"
MANIFEST_JSON = REPO_ROOT / "manifest.json"
PYPROJECT_TOML = REPO_ROOT / "Server" / "pyproject.toml"
SERVER_README = REPO_ROOT / "Server" / "README.md"
ROOT_README = REPO_ROOT / "README.md"
ZH_README = REPO_ROOT / "docs" / "i18n" / "README-zh.md"


def load_package_version() -> str:
    """Load version from package.json."""
    if not PACKAGE_JSON.exists():
        raise FileNotFoundError(f"Package file not found: {PACKAGE_JSON}")

    package_data = json.loads(PACKAGE_JSON.read_text(encoding="utf-8"))
    version = package_data.get("version")

    if not version:
        raise ValueError("No version found in package.json")

    return version


def update_package_json(new_version: str, dry_run: bool = False) -> bool:
    """Update version in MCPForUnity/package.json."""
    if not PACKAGE_JSON.exists():
        print(f"Warning: {PACKAGE_JSON.relative_to(REPO_ROOT)} not found")
        return False

    package_data = json.loads(PACKAGE_JSON.read_text(encoding="utf-8"))
    current_version = package_data.get("version", "unknown")

View on GitHub (pinned to c21bf496bc)

Solutions

1. Confirm the file exists: ls MCPForUnity/package.json from the repo root.
2. Run the script from within the repo, or ensure parents[1] of the script path resolves to the actual repo root.
3. If you know the version, bypass auto-detection by passing --version explicitly (update_versions.py only calls load_package_version when --version is absent).

Example fix

# before — auto-detect fails because package.json is missing
python3 tools/update_versions.py

# after — supply version explicitly to skip the missing-file read
python3 tools/update_versions.py --version 9.2.0

from pathlib import Path

PACKAGE_JSON = Path("MCPForUnity").resolve() / "package.json"
if not PACKAGE_JSON.is_file():
    raise SystemExit(f"{PACKAGE_JSON} not found. Run from the repo root or pass --version.")

When it happens

Trigger: Running update_versions.py from outside the repo, or with the script copied/moved so that parents[1] doesn't resolve to the real repo root. Also fires in a shallow clone or worktree that excludes the MCPForUnity directory.

Common situations: Script invoked from a different working directory; the repo was only partially cloned; the script was symlinked or copied to a tools/ directory in a different project; MCPForUnity/package.json was deleted or not yet created in a fresh branch.

Related errors

• Source MCPForUnity folder not found: {source_mcp}
• Assets folder not found: {assets_dir}
• Expected file not found: {f}
• No version found in package.json
• Could not generate a unique screenshot filename for '{fullPa

AI-assisted analysis of CoplayDev/unity-mcp@c21bf496bc (2026-08-13). Data as JSON: /api/errors/8bf6a71ade884374. Report an issue: GitHub.